Continuous circulation sand filter and continuous circulation sand filtering method

Abstract

Provided is a continuous circulation sand filter including a filtering barrel filled with a sand filtering layer, an inflow tube for introducing raw water into the filtering barrel, a treated water discharge part for discharging treated water purified by passing the raw water through the sand filtering layer from a lower end of the sand filtering layer to an upper end thereof, an air lift tube for transferring contaminated sand, located in the lower end of the sand filtering layer, from a lower part of the filtering barrel to an upper part thereof, a transfer water discharge filter contacting the air lift tube to discharge transfer water moved upward together with sand through the air lift tube and trap the sand and a foreign substance, a descent guide tube downwardly moving the sand and the foreign substance moved to the upper part of the filtering barrel through the air lift tube, and a foreign substance separation tube suctioning the downwardly moving foreign substance to remove the foreign substance from the downwardly moving sand, and discharging the foreign substance.

The invention claimed is: 
     
       1. A continuous circulation sand filter comprising:
 a filtering barrel filled with a sand filtering layer; 
 an inflow tube for introducing raw water into the filtering barrel; 
 a treated water discharge part for discharging treated water purified by passing the raw water through the sand filtering layer from a lower end of the sand filtering layer to an upper end thereof; 
 an air lift tube for transferring contaminated sand, located in the lower end of the sand filtering layer, from a lower part of the filtering barrel to an upper part thereof; 
 a transfer water discharge filter contacting the air lift tube to discharge transfer water moved upward together with sand through the air lift tube and trap the sand and a foreign substance; 
 a descent guide tube downwardly moving the sand and the foreign substance moved to the upper part of the filtering barrel through the air lift tube; and 
 a foreign substance separation tube suctioning the downwardly moving foreign substance to remove the foreign substance from the downwardly moving sand, and discharging the foreign substance. 
 
     
     
       2. The continuous circulation sand filter according to  claim 1 , wherein the transfer water discharge filter comprises a mesh formed of a metal. 
     
     
       3. The continuous circulation sand filter according to  claim 1 , wherein a suction pump is disposed on the foreign substance separation tube to forcibly discharge a foreign substance. 
     
     
       4. The continuous circulation sand filter according to  claim 1 , wherein the transfer water discharge filter is disposed on an upper end of the air lift tube such that transfer water passes through the transfer water discharge filter. 
     
     
       5. The continuous circulation sand filter according to  claim 1 , further comprising an air inflow tube compressing air to supply the compressed air to a lower end of the air lift tube,
 wherein upward moving force of the compressed air upwardly moves the contaminated sand within the air lift tube. 
 
     
     
       6. A continuous circulation sand filtering method comprising:
 supplying raw water to a sand filtering layer and moving the raw water to an upper part of the sand filtering layer to filter the raw water, thereby producing treated water; 
 upwardly moving contaminated sand and transfer water by using upwardly moving air, so as to separate the contaminated sand and the transfer water into a foreign substance, sand, and the transfer water; 
 separating the foreign substance, the sand, and the transfer water into the transfer water, as a liquid, and the sand and the foreign substance as solids; 
 discharging the transfer water together with the treated water; and 
 separating the sand and the foreign substance from each other. 
 
     
     
       7. The continuous circulation sand filtering method according to  claim 6 , wherein a filter is used to separate the foreign substance, the sand, and the transfer water into the liquid and the solids. 
     
     
       8. The continuous circulation sand filtering method according to  claim 6 , wherein in the separating of the sand and the foreign substance, the sand and the foreign substance are moved downward. 
     
     
       9. The continuous circulation sand filtering method according to  claim 8 , wherein the foreign substance separated by downwardly moving the sand and the foreign substance is discharged through suction. 
     
     
       10. The continuous circulation sand filtering method according to  claim 8 , wherein a descent guide tube and a foreign substance separation tube obliquely diverging upward from a side surface of a lower end of the descent guide tube are used to separate the sand and the foreign substance.